What they are: Phthalates are part of a family of chemicals that allow makeup and lotions to penetrate the skin, make nail polish flexible and help fragrances last longer.

Health concerns: Because phthalates mimic hormones including estrogen, researchers say they suspect the chemicals affect the onset of puberty in girls. One study linked high levels of phthalates with early breast development. Other studies indicate phthalates might disrupt hormones in boys prenatally. Cosmetics containing some phthalates are banned in Europe. The ban in the United States covers any toy that can be placed in a child’s mouth, including dinnerware, pacifiers and teethers, as well as toys that contain a certain level of phthalates.

Stay safe: Avoid products that aren’t marked phthalate-free, especially those that are heavily fragranced. Although phthalates might not be listed in the ingredients, the word fragrance can often be a clue that the product contains dozens of chemicals, including phthalates. The good news is that some manufacturers, including Alba and Unilever, are working to phase out some of those chemicals. Products such as Avalon Organics lotions and shampoos are phthalate-free already. OPI, Orly, Sally Hansen and other nail polish companies have removed one phthalate from their nail polish.